seti is a interesting group that is searching the universe by listening. They are looking for radio frequencies in the universe that statistically are unlikely to occur without being caused by intelligent life. It would be like digging in the dirt, looking for something organized or structured. If you dug in the dirt and found a watch you would assume that something intelligent created it. The strength of the single caused by a radio wave never fully goes to zero. As far as I can tell it echoes through the entire universe. This makes it a good material to search through. Seti has been searching for some time now, and has found nothing. Here are three reasons why seti may have found nothing. 1.)intelligent life is very rare or non existant 2.)intelligent life that communicates or uses radio waves is very rare or non existant 3.)when intelligent life communicates it looks like white noise. #3 is the most interesting to me. Humans have been using radio waves for a period of time that is measureable in 10s of years. Its an invisiably short amount of time in comparison to the life of earth, or the solar system, or the universe. In this tiny amount of time we have gone from radio technology that looks like morse code, to a spread spectrum, wide band, digital compressed, encrypted signal that looks more like white noise then ever. The better our compression technology gets, the more our signals look like white noise. In fact I think there is actual theories to back this up. This is because as soon as an inteligent creature trying to communicates discovers a pattern in what they are communicating, they compress the pattern out. Rather then sending Qu all the time you can just send Q...and the pattern leaves the signal. I think, in another 500 years, our civilizations communication waves will look entirely like random noise and fade into the natural background noise of outer space. So, rather then futilely trying to listen for the random noise of an intelligent civilization it might be more affective to search for life with a transmission. This of course isn't a new idea. The author of antinomian.com pointed me over too Karen Carpenter who was influenced by John Woloschuk of Klaatu.